Rebekka Armstrong left her small, desert hometown of Ridgecrest, California, at age 18, going to Los Angeles to be in Playboy.

She'd submitted her pictures on a whim and was chosen as the September 1986 playmate of the month. As a Playboy ambassador, she starred in TV shows and movies, won elite modeling gigs and partied with celebrities.

She didn't know then that she was HIV positive. She found out three years later, after going in for a pregnancy test. "I thought, 'How is this happening to me?'" she said.

The good news is that Armstrong is still alive — and thriving. She has trained for years as a bodybuilder and lives with her husband, Anthony Dispirito, just north of Los Angeles with their four dogs, which they call their "children."

Her main passion is spreading awareness about AIDS prevention. "Every hour of the day two young people aged 14 to 24 are infected," she said, "and that's a conservative estimate." She will tell her story and preach her message at Missouri State on Monday, for World AIDS day.

Times have changed dramatically since she was infected. Before the turn of the millennium, contracting AIDS was regularly a death sentence. Her friend, the rapper Eazy-E, for example, died only weeks after learning he had the disease in 1995. Now, with the help of the proper medicine, AIDS patients like Armstrong can live a long and healthy life. But unfortunately, she says, this presents a whole new set of challenges.

"People might think, 'Yeah, if I'm exposed to it, I can just take a pill,'" she said. "But everybody's body is going to respond differently to being infected. How are you going to deal with it emotionally and physically? There are so many factors."

Armstrong today is happy with her life, but it was a long and tortured path to get here. She's not sure how she got the disease. Upon receiving her positive diagnosis in 1989, she contacted all of her former partners. But they all said they were negative. Armstrong also received a blood transfusion as a teenager but was unable to determine if she'd been given infected blood. At the end of the day, "I'm the one who gave myself HIV," she said, emphasizing that safe sex is everyone's personal responsibility.

It would be years before she would talk openly about her disease. After receiving her diagnosis, she began "self-medicating" with alcohol and drugs, she said.

"I was pretty much buzzed at any given time," she said, adding that her mentality was: "I am going to snort this line and drink this six-pack of beer because I don't want to think about it."

Another problem was that the AIDS drugs were very primitive at the time. She took AZT, which caused her to suffer everything from nerve damage and nausea to vomiting and diarrhea. "I felt like my head was a bowling ball."

Around 1993, she hit rock bottom. She attempted suicide by taking just about everything in her medicine cabinet and landed herself in a coma. "I couldn't have felt more ashamed, dirtier, and uglier, and I just wanted to disappear," she said. But she survived and pledged to turn her life around. She began receiving support from the AIDS Project Los Angeles and decided to go public with her story.

She appeared on the cover of gay and lesbian magazine The Advocate in September 1994. With her sweater sliding off her shoulder and wearing a tiara, she appeared next to the headline, "Portrait of an HIV-Positive Lesbian Centerfold." It was a dual coming out: As a carrier of the disease and as gay, although in the article she said she was bisexual.

Playboy and Hugh Hefner supported her during this difficult time, but her revelations sent shock waves around the nation. She was the first Playmate to contract HIV and, along with Magic Johnson, became a celebrity face of the disease. Meanwhile, she turned her life around, entering recovery for drugs and alcohol. She later trained as a competitive bodybuilder. It took a lot of willpower, she said, especially on days when her medication left her feeling weak.

Most important, she began dedicating herself to educating others about the dangers of unprotected sex, particularly young adults. She has traveled the world over to spread her message, and her website is full of comments from students and educators who have been inspired by her talks.

Armstrong says her education mission has given her life a great meaning.

"I like to constantly think positive," she concludes. "As positive as one can."

World AIDS Day at MSU

Rebekka Armstrong speaks from 7 to 8 p.m. Monday at the Plaster Student Union at Missouri State university. Her talk will be followed by a Q&A and a meet and greet. The event is free. More details can be found at calendar.missouristate.edu.